I mean - you walk around, there are monsters on the map that will attack you when they see you (some of them will attack you when you attack them first), you fight in real time, use some spells, runes, heal etc. When monsters die, there are corpses on the ground, which you can loot (% chance for some items), you get experience points and you level up after getting enough experience. Monsters respawn after some time. (Watch the movie in the spoiler, it says more than thousand words).

Yes, the scripts are usually called ABS (Action Battle System). There are several around. I actually made one myself. http://forum.chaos-project.com/index.php/topic,106.0.htmlIt reminds more of Secret of Mana than Tibia, but it's flexible enough that you can make anything with it. There are a few example games as well (two of which I made myself).